Cylindrical furnace for continuous production of reinforced and nonreinforced seamless pipes of foam glass

ABSTRACT

Foam glass is poured into a vertical annular chamber of a furnace through a header which rotates with reference to the furnace about the chamber axis to deposit the glass in the chamber as a helical layer; the temperature of the chamber is controlled to let the glass layer harden into a pipe as it descends. Extraction rollers beneath the chamber continuously remove the newly produced pipe from the furnace.

United States Patent Velev Oct. 23, 1973 [54] CYLINDRICAL FURNACE FOR3,527,587 9/1970 Velev et al 65/22 CONTINUOUS PRODUCTION OF 3,574,5834/1971 Goldsmith 65/22 3,404,203 10 1968 Donald 264/209 x REINFORCED ANDNONREINFORCED 2,620,597 12/1952 Ford 65 22 SEAMLESS PIPES OF FOAM GLASSDimitar Spassov Velev, Rousse, Bulgaria Inventor:

Assignee: Nis Pri Vimmess, Rousse, Bulgaria Filed: Nov. 15, 1971 Appl.No.: 198,777

Related US. Application Data Continuation-impart of Ser. No. 179,528,Dec. 16, l97l, abandoned, Continuation of Ser. No. 778,455, Nov. 25,I968, abandoned.

US. Cl 65/144, 65/18, 65/146, 7 264/176 R, 264/209 Int. Cl C03b 19/06Field of Search 65/18, 22, 88, 87, 65/141, 335, 144; 264/176 R, 209

References Cited UNITED STATES PATENTS 12 1966 Rosenbaum 65/22 x FOREIGNPATENTS OR APPLICATIONS 330,943 6/1930 Great Britain 65/144 PrimaryExaminerRobert L. Lindsay, Jr. Attorney-Karl F. Ross [57] ABSTRACT Foamglass is poured into a vertical annular chamber of a furnace through aheader which rotates with reference to the furnace about the chamberaxis to deposit the glass in the chamber as a helical layer; thetemperature of the chamber is controlled to let the glass layer hardeninto a pipe as it descends. Extraction rollers beneath the chambercontinuously remove the newly produced pipe from the furnace.

10 Claims, 2 Drawing Figures 7 HEATING THEM-1N6 CYLINDRICAL FURNACE FORCONTINUOUS PRODUCTION OF REINFORCED AND NONREINFORCED SEAMLESS PIPES OFFOAM GLASS This application is a continuation-in-part of my pendingapplication Ser. No. 179,528 filed Dec. 16, 1971 as a streamlinedcontinuation of my application Ser. No. 778,455 filed Nov. 25, 1968 bothnow abandoned.

My present invention relates to an apparatus for producinglarge-diameter pipes of foamed glass, with or without internalreinforcements, by a continuous process with the aid of an upright kilnor furnace forming a vertical heating chamber.

A kiln of this general type has been disclosed in US. Pat. No. 3,527,587issued Sept. 8, 1970 to D5. VELEV et al. In the system of this priorpatent, a charge of foamable glass is continuously introduced into theheating chamber at the top of the kiln in which it progressivelydescends in the form of a hardeningv column extracted by frictionrollers beneath the open bottom of the chamber. The charge is heated inthe upper part and forcedly cooled in the lower part of the chamber;each fresh layer of foamable glass, deposited on the top of thedescending column, homogeneously blends with the body of that column.This process, therefore, enables the formation of foam-glass rods orbars of indefinite length which can then be cut to size as desired.

The general object of my present invention is to provide an apparatussuitable for the continuous production, in a basically similar manner,of tubular rather than solid stock of foam glass.

One of the problems encountered in shaping such tubes or pipes in a kilnis the need for providing a central core which must be so mounted as notto interfere with the supply of foamable glass to the annular chamberdefined by that core and the surrounding furnace wall. A related problemis that of evenly distributing the glass mass about the core to insureuniform thickness and strength of the product. Difficulties arise alsofrom the fact that the hardening glass, sandwiched between the chamberwall and the core, tends to adhere to the core surface as it shrinks inthe lower portion of the chamber designed as a cooling zone.

A more particular objectof my present invention, therefore, is toprovide an apparatus for the purpose set forth which avoids theaforestated difficulties.

These objects are realized, pursuant to my present invention, by theprovision of a header overlying the kiln coaxially with the annularheating chamber thereof, the kiln and the header being provided withdrive means for relatively rotating same about their vertical axisduring operation of a feeder which is carried on the header and includesa hopper for the continuous delivery of foamable glass mass to the topof the chamber. A restricted neck at the top of this chamber,advantageously formed by concentric rings of refractory material,maintains annular clearances between the inner and outer chambersurfaces, on the one hand, and the descending tubular glass bodycontinuously formed therebetween, on the other hand. Advantageously, notonly the kiln wall or shell but also the header and the core areprovided with temperaturecontrol means for heating that body in theupper part and cooling it in the lower part of the chamber.

Internal reinforcements, such as wire strands, may be continuouslyintroduced into the annular chamber by a supply mechanism also mountedon the header.

At the beginning of operations, when the kiln is empty, the bottom ofthe chamber may be plugged by a temporary support for the initialcharge, this support advantageously taking the form of an annularplatform which is mounted on an elevatable base and fits closely betweenthe two refractory annular shoulders forming the reduced neck. Theprogressive lowering of the base and of the supporting platform lets thecharge descend at the required speed, correlated with the rate offeeding, to the bottom of the chamber where the hardened glass tube isgripped by extraction means such as friction rollers.

The invention will be described in greater detail hereinafter withreference to the accompanying drawing in which:

FIG. 1 shows, in vertical section, an apparatus according to theinvention in operating condition; and

FIG. 2 is a view similar to F 1G. 1, showing the apparatus at the startof operations.

The apparatus shown in the drawing comprises a kiln l in the form of acylindrical shell with a cylindrical core 2 defining between them anannular heating chamber 30. A header 3 carries a hopper 4 for acontinuous feeding of foamable glass mass into the space 30. Kiln l andheader 3 are relatively rotatable, about their common axis 0, with theaid of drive means here diagrammatically represented by a motor 26 whoseshaft 27 carries a pinion 28 in mesh with peripheral teeth 29 of theheader. Motor 26 is mounted on a beam 17 which is structurally integralwith kiln 1 and also carries a rod 15 from which the core 2 issuspended, the rod passing through a central bore 16 of the header 3 andserving as a journal bearing therefor.

For the purpose of this description it will be assumed that the kiln isstationary while the header rotates.

Also mounted on header 3 are a pair of counterrotating rollers 5 servingto introduce a reinforcing wire 25'into the chamber 30; the drive ofrollers 5 may be synchronized in any convenient manner with the rotationof the header. Such rotation is facilitated by the provision of ballbearings 31 at the top of the kiln l.

Hopper 4 supplies the charge to an outlet tube 32 which may contain, forexample, a continuously rotating feed screw synchronized with the rotarydrive. The

material issuing from tube 32v is kept at the desired elevatedtemperature by heating means 6 on header 3, here shown as a set ofchannels at its lower surface which may accommodate electric heatingelements or conduits traversed by a hot fluid. A similar heater 7 isdisposed in the wall of kiln 1 near the top thereof, at the level of arestricted foaming zone of chamber 30 defined by a pair of concentricannular strips 18, 19 projecting from the outer and inner chamber walls.These strips may consist, for example, of a sintered mixture of carbonand refractory particles.

Within the restricted zone so defined, the feeding tube 32 deposits acontinuous foaming layer 13 of helical configuration on a tubular body12 of foam glass exiting at a corresponding rate from the lower end ofthe kiln 1 under traction from a pair of friction rollers 10 driven atthe proper speed in synchronism with the feeding mechanism. Uniformthickness of layer 13 is achieved with the aid of a doctor blade 14 onheader 3 electrically heated via wires 33. The temperature of theprogressively descending tube 12 is controlled by further heating means8 in the kiln wall and supplemental heaters 8' in the core, similar tothe elements 6, 7 described above, and by cooling means 9, 9 at a levelbelow the heating zone, e.g., sets of channels in shell 1 and core 2traversed by a low-temperature fluid. It will be noted that coolingbegins along the lower part of core 2 but that the outer coolingelements 9 continue below the end of the core. A horizontal cutting disk11, on a carriage (not shown) guided for travel around the furnace axis0, may be swung inwardly to sever the tube 12 after a predeterminedlength thereof has been produced.

At the beginning of a production cycle, with furnace chamber 30 empty offoam glass, an annular platform 21 closely fitting between rings 18 and19 plugs the neck of the chamber to receive the initial charge (see FIG.2). Platform 21 is supported by means of stays 23 on a base 24 having acentral stem 22 by which it may be raised and lowered, e.g.,hydraulically, under the control of a servomotor not shown. As themolten glass mass is poured in, support 21 gradually descends at a speedcommensurate with the rate of feed until it clears the extractionrollers 10. The assembly 21 24 may then be moved out of line with thekiln 1 so as not'to hinder the further descent of the glass tube 12. Thefirst-formed piece of tubing, shaped somewhat irregularly, maythereafter be cut off by the rotating disk 11.

In operation, theheaters 6, 7 and 7' may maintain a temperature of about850 to 950C in the foaming zone. Below that zone, the temperature may beheld at about 550 to 650 by the ancillary heaters 8 and 8'. The top tierof coolers 9, 9 reduces this temperature to approximately 500C whence itdrops gradually to 50C at the level of the extraction rollers 10.

It will be noted that the annular shoulders 18, 19 of the foaming zonemaintain clearances between the body of tube 12 and the core 2 as wellas the shell 1.

The system herein disclosed may operate with a low specific input ofheat, e.g., of 400 to 800 kcal per kg of foam glass, and can be fullyautomated while being simple in structure and inexpensive to build andmaintain. it is particularly useful for the production of pipes of largediameters, e.g., for the insulation of steam ducts and otherfluid-carrying conduits.

I claim:

1. An apparatus for producing foamed-glass pipe, comprising:

a kiln including an upstanding central core and a cylindrical shellcoaxially surrounding said core with formation of an annular chambertherebetween, said chamber having a restricted neck at the top; a headercoaxially overlying said kiln, said header having an outletcommunicating with said neck;

feed means on said header for continuously delivering a foamable glassmass through said outlet to said chamber;

drive means for relatively rotating said header and said kiln abouttheir axis during operation of said feed means;

temperature-control means on said header and on said kiln for causingsaid mass to harden into a pipe on leaving said neck and descending insaid chamber; and

extraction means on said kiln below said shell for continuously pullingthe hardened pipe out of the lower end of said chamber.

2. An apparatus as defined in claim '1 wherein said shell and said coreare provided at their top with confronting annular shoulders defining arestricted portion of said chamber.

3. An apparatus as defined in claim 2 wherein said shoulders consistessentially of refractory material.

4. An apparatus as defined in claim 2 wherein said temperature-controlmeans comprises heating means on said header and on said shell in theregion of said re 7 stricted portion and cooling means on said shell ata level substantially below said restricted portion.

5. An apparatus as defined in claim 4 wherein said temperature-controlmeans further comprises supplemental heating means and cooling means onsaid core respectively confronting the heating means and cooling meanson said shell.

6. An apparatus as defined in claim 5 wherein said core terminates abovethe bottom of said shell, the cooling means on said shell extendingbeyond the lower end of said core.

7. An apparatus as defined in claim 1, further comprising supply meanson said header for continuously delivering an elongated reinforcement tosaid chamber.

8. An apparatus as defined in claim 1, further comprising a temporarysupport for said mass introducible from below into said chamber forreceiving an initial charge from said feed means.

9. An apparatus as defined in claim 8 wherein said temporary supportcomprises an annular platform.

10. An apparatus as defined in claim 9 wherein said chamber has arestricted neck portion at its top, said platform fitting closely intosaid neck portion.

1. An apparatus for producing foamed-glass pipe, comprising: a kilnincluding an upstanding central core and a cylindrical shell coaxiallysurrounding said core with formation of an annular chamber therebetween,said chamber having a restricted neck at the top; a header coaxiallyoverlying said kiln, said header having an outlet communicating withsaid neck; feed means on said header for continuously delivering afoamable glass mass through said outlet to said chamber; drive means forrelatively rotating said header and said kiln about their axis duringoperation of said feed means; temperature-control means on said headerand on said kiln for causing said mass to harden into a pipe on leavingsaid neck and descending in said chamber; and extraction means on saidkiln below said shell for continuously pulling the hardened pipe out ofthe lower end of said chamber.
 2. An apparatus as defined in claim 1wherein said shell and said core are provided at their top withconfronting annular shoulders defining a restricted portion of saidchamber.
 3. An apparatus as defined in claim 2 wherein said shouldersconsist essentially of refractory material.
 4. An apparatus as definedin claim 2 wherein said temperature-control means comprises heatingmeans on said header and on said shell in the region of said restrictedportion and cooling means on said shell at a level substantially belowsaid restricted portion.
 5. An apparatus as defined in claim 4 whereinsaid temperature-control means further comprises supplemental heatingmeans and cooling means on said core respectively confronting theheaTing means and cooling means on said shell.
 6. An apparatus asdefined in claim 5 wherein said core terminates above the bottom of saidshell, the cooling means on said shell extending beyond the lower end ofsaid core.
 7. An apparatus as defined in claim 1, further comprisingsupply means on said header for continuously delivering an elongatedreinforcement to said chamber.
 8. An apparatus as defined in claim 1,further comprising a temporary support for said mass introducible frombelow into said chamber for receiving an initial charge from said feedmeans.
 9. An apparatus as defined in claim 8 wherein said temporarysupport comprises an annular platform.
 10. An apparatus as defined inclaim 9 wherein said chamber has a restricted neck portion at its top,said platform fitting closely into said neck portion.